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The kick-start technique in competitive swimming generates a force acting on the starting platform owing to gravity, muscle contraction and resulting joint torque. To understand optimal body movement on the starting platform for maximising take-off velocity, it is necessary to investigate the joint torque in relation to the joint's rotation effects. Joint torques were calculated by inverse dynamics using kinetic and kinematic data. A one-way ANOVA showed significantly greater extensional torque for shoulders than for elbows or wrists, and for hips than for knees or ankles. The results indicated that the force of the hands was mainly influenced by extension torque at the shoulder joint. Hip joint extension torque on the front side lower limb (FSLL) was mainly used for supporting the body weight until hands off. After hands off, the front-foot force originated mainly by increases in ankle joint plantar flexion and knee joint extension torque on the FSLL. Rear side lower limb torque increases in the hip, knee and ankle joints provided the rear-foot force. This investigation clarified the magnitudes and functions of each joint torque acting on the extremities during the kick-start, providing practical information for improving starting performance.

This study compares polyrhythmic production ability between water polo players (WPs), artistic swimmers (ASs) and drummers (Ds), to assess how their differing experiences in coordinating complex inter-limb activity with music affected this ability. Eight ASs, eight WPs and eight Ds participated. They were asked to perform finger and foot taps in a single-rhythm task (every 750 ms) and two polyrhythmic tasks (finger and foot taps at 750 and 500 ms, respectively, and vice versa). The percentage of correct response cycles (PCRC), subjective difficulty scores were collected and analysed using a two-way mixed analysis of variance (ANOVA) and coefficients of variation of the inter-tap interval (CVITI) were collected and analysed using a three-way mixed analysis of variance (ANOVA). The three groups showed no statistically significant differences in the single-rhythm task. However, on polyrhythmic tasks, the WPs were significantly outperformed by the other two groups in PCRC and CVITI. These results suggest that the experience of coordinating limbs with music has positive impacts on polyrhythmic production ability. They also imply that ASs and Ds have similar polyrhythmic production ability despite the apparent differences in task complexity in their daily training and performances.

The purpose of this study was to compare active drag during front-crawl swimming performed by competitive swimmers with passive drag acting on the same group of swimmers with a streamlined position at various velocities. Seven male competitive swimmers participated in this study, and the testing was conducted in a swimming flume. Active drag was evaluated for front-crawl swimming with upper and lower limb motion using a methodology that estimates the drag in swimming using measured residual thrust values (MRT method). Passive drag was measured by a load cell connected to the swimmers with a streamlined position using a stainless-steel wire. In each case, drag was estimated at six staged velocities ranging from 1.0 to 1.5 m/s. To compare the drags at various velocities, we calculated coefficients a and b by applying the measured force value at each velocity to the equation D = a vb (D: drag, v: velocity). The active drag estimated from the MRT method (a = 35.7 ± 5.3, b = 2.80 ± 0.22) was larger than passive drag (a = 23.6 ± 3.1, b = 2.08 ± 0.23). Furthermore, the difference between active and passive drag was large at high velocities. Therefore, it is possible that the effects of factors other than posture and/or body shape have a large influence on active drag, especially at high velocity.

The purpose of this study was to clarify how elite artistic (synchronised) swimmers generate fluid forces with their hands during two kinds of sculling motions: flat sculling in the back-layout position and support sculling in the vertical position. We used the pressure-distribution measuring method to estimate unsteady fluid forces acting on the hand during sculling motions performed by seven elite artistic swimmers. In addition, we simultaneously analysed sculling motions using three dimensional-direct linear transformation methods. We found that sculling motions continuously generated fluid forces that are large during the stroke phase and small during the transition phase. Lift force was efficiently generated, and a large upward propulsive force was obtained during the stroke phase in both flat and support sculling. During the outside transition from out- to in-sculling, the net vertical load (= gravitational force-buoyant force) was supported by the drag force. In both flat and support sculling, artistic swimmers generated an even fluid force in the upward direction during the in-sculling and out-sculling phases to maintain a stable position.

This study is aimed at analysing the scientific literature related to physiological responses in synchronized swimmers, produced from 2006 to 2016. A systematic review was conducted using electronic databases (Google Scholar, PubMed, SportDiscus, Web Science, Scielo and Scopus) in national and international journals. The articles were selected using the following inclusion criteria: composed samples of synchronized swimmers of both sexes, articles in English, Spanish and Portuguese, published from 2006 to 2016. Ten studies were included. The concentration of the articles and their publication was as follows: Europe (77%) and North America (23%). The protocols used analyse physiological responses in synchronized swimmers athletes during competitions or laboratory tests, lactate measurements, heart rate, rates of perceived exertion, VO2 and lung volume. The subjects of 100% of the studies included in this review were athletes of junior and senior categories who volunteered. Only 03 of the 10 studies have compared the physiological responses in volunteers who were not synchronized swimmers to synchronized swimmer athletes. The studies were conducted using different methodologies, which makes it difficult to compare them, so the standardization of instruments and definitions is essential for the scientific advancement in this field. In addition, it would be interesting to expand the research of these physiological responses in synchronized swimmers using base level or beginners as sample.

Recently, body height is considered as one of the major elements for synchronized swimmers to acquire high performance score. The aim of the study was to compare body height and proportion of Japanese female synchronized swimmers in elementary school to age-matched normal female Japanese or other Caucasian populations, by using charts of body height and proportion of girls in Japan. Subjects were nationwide synchronized swimmers of forth to sixth grade in elementary school, who participated in the audition for executing with the committee of synchronized swimming in Japan Swimming Federation. Body height and sitting height were measured for these athletes to evaluate body proportion. On the other hand, the data of girls in Japanese and Caucasian populations evaluated by the previous studies were used for comparison. As a result, body height and proportion in synchronized swimmers were similar and superior to those of general Japanese, respectively. However, those values were lower and inferior to those of general Caucasians, respectively. There were a limited number of Japanese athletes who had the comparable body shape to normal Caucasian.

Idiopathic pulmonary fibrosis (IPF), a chronic progressive lung disease of unknown etiology, is characterized by the expansion of myofibroblasts and abnormal deposition of extracellular matrix in the lung parenchyma. To elucidate the molecular mechanisms that lead to IPF, we analyzed myofibroblasts established from patients with IPF by oligonucleotide microarrays. Gene expression profiles clearly suggested that lipid peroxidation is enhanced in myofibroblasts, which was confirmed by measuring cellular lipid hydroperoxides. One of the most highly up-regulated proteins in myofibroblasts was selenoprotein P, an antioxidant protein not previously associated with IPF. Subsequent analysis demonstrated that selenoprotein P reduces lipid hydroperoxides and maintains the viability of myofibroblasts. Thus, our results reveal a novel pathophysiologic function of myofibroblasts as a generator of lipid hydroperoxides, and a self-defense mechanism against self-generated oxidative stress.

We investigated coaching points for the technique of the eggbeater kick in synchronized swimming. The movements of the eggbeater kick for six female synchronized swimmers, all the top-ranking members at the Olympics and World Championships, were analyzed by using three-dimensional motion analysis. By comparing the movements of higher eggbeater-skilled swimmers with lower eggbeater-skilled swimmers, the coaching points for techniques of the eggbeater kick in synchronized swimming are clarified as follows. First, to hold the knees as high and as near the water surface as possible and to keep the heels close to the hips. Secondly, to keep the knees as wide as possible. Thirdly, to kick sideways producing lift force, and not to kick downward. Fourthly, to pull up the heels to nearly the water surface at the out-kick, with strong internal rotation of the thighs. Lastly, to move the feet as if treading water, with strong dorsiflexion and plantar flexion and adduction of the foot; that is to move the feet like the motion of the hands when sculling. Moreover, the movements of higher eggbeater-skilled swimmers can be termed 'horizontal kick type' and the movements of lower eggbeater-skilled swimmers can be termed 'vertical kick type'.

Data from previous studies provided the mean values of body proportions for each age group of healthy Japanese children, but not the standard curves describing the distribution.The aim of the study was to construct a chart of body proportion of girls and boys in Japan.About 4% of the nationwide student population in Japan, more than 20,000 children per group of both boys and girls of all ages, was included randomly. The upper/lower ratio (ULR) was calculated from correlation tables containing stature and sitting height data reported in the Statistical Report on School Health and Hygiene. The subischial leg length was calculated by subtracting sitting height from stature.The present study showed that Japanese boys (13.5-17.5 years old) were taller and had relatively longer legs than Japanese girls in the same age group, and that the median ULRs of Japanese girls and boys (5.5-17.5 years old) were larger than the average of Caucasian girls and boys reported previously. In boys, the percentile values reached the lowest at 13.5 years, then increased slightly. On the other hand, in girls, the percentile values remained constant after 11.5 years, which is different in boys in the present study and in other Caucasian populations obtained from several studies.The new chart provides useful information in the assessment of the body proportions of Japanese children.

To determine the daily energy requirement of elite synchronized swimmers during moderate-intensity training, the average daily energy expenditure measured by the doubly labeled water method, was calculated for nine female Japanese national team synchronized swimmers [four senior; mean (SD) 22.5 (1.0) years old, 52.2 (3.6) kg, and five junior; 17.6 (1.1) years old, 52.8 (2.3) kg]. Their total energy expenditure (TEE) was 11.5 (2.8) MJ x day(-1) [2738 (672) kcal day(-1)]. When compared with estimated energy requirements derived from "Recommended Dietary Allowances for the Japanese", 12.1 (0.6) MJ day(-1) [2897 (139) kcal day(-1)], there was no difference between mean actual and estimated energy requirements. However, there were considerable differences observed on an individual basis. Their energy intake, estimated from 7- day self-reported dietary records, was 8.9 (1.7) MJ day(-1) [2128 (395) kcal x day(-1)], which was significantly lower than their TEE (P0.05). Resting energy expenditure (REE), as determined by indirect calorimetry, was 5.2 (0.3) MJ x day(-1) [1247 (75) kcal x day(-1)]. Their physical activity level (TEE/REE) was 2.18 (0.43). These results demonstrate that the TEE values of elite female synchronized swimmers are not dissimilar to those reported for athletes participating in other sports, especially competitive swimmers during moderate-intensity training.